Hurricane Irma regained strength as it made landfall in Florida as a Category 4 storm.
At about 6 this morning it was downgraded to a Category 3 storm, and then to a Category 2.
US President Donald Trump has declared a major disaster for Florida.
The hurricane has sustained wind speeds reaching 177km/h, down from 209km/h earlier. It is the most powerful Atlantic storm in a decade.
In Naples, Florida, water levels have climbed 2 metres in 90 minutes. As the eye of the storm passed, it presented the more dangerous issue of storm surge.
Three people have died in two separate car crashes related to Hurricane Irma.
The US National Hurricane Centre tweeted that people in the area of Naples and Marco Island should move away from the coast as storm surges of up to 15ft were possible.
There is dead calm and people have been out on the streets, but the storm surge is expected to come later.
The storm is now heading for the Tampa Bay area, with a population of about three million. The region has not been hit by a major hurricane since 1921.
